diff --git a/containers/libreportal/frontend/js/components/app/port-manager.js b/containers/libreportal/frontend/js/components/app/port-manager.js
index 87ab288..d899205 100755
--- a/containers/libreportal/frontend/js/components/app/port-manager.js
+++ b/containers/libreportal/frontend/js/components/app/port-manager.js
@@ -380,8 +380,8 @@ class PortManager {
               <input type="text" class="port-url-path" placeholder="e.g. /,/results/stats.php" value="${port.url_path || ''}" data-index="${index}">
             </div>
             <div class="port-field port-field-advanced">
-              <label>Subdomain <span class="help-icon" title="Override the Traefik subdomain for this port (e.g. 'streaming.app' → streaming.app.example.com). Leave empty to inherit the app's CFG_HOST_NAME. Parsed by the framework; label-generation refactor pending.">?</span></label>
-              <input type="text" class="port-subdomain" placeholder="(inherit hostname)" value="${port.subdomain || ''}" data-index="${index}">
+              <label>Subdomain <span class="help-icon" title="The subdomain this port is served on — e.g. 'vault' → vault.example.com, or 'admin.app' for a multi-level host. Use @ for the root of your domain. Leave empty to default to the app's name.">?</span></label>
+              <input type="text" class="port-subdomain" placeholder="vault  ·  @ = root  ·  blank = app name" value="${port.subdomain || ''}" data-index="${index}">
             </div>
           </div>
         </div>